HSEES Contacts

Annual Report 1997

Historical Document

This document is provided by the Agency for Toxic Substances and Disease Registry (ATSDR)
ONLY as an historical reference for the public health community. It is no longer being maintained and the data
it contains may no longer be current and/or accurate.

In 1980, Congress created the Agency for Toxic Substances and
Disease Registry (ATSDR) to implement health-related sections
of laws that protect the public from hazardous wastes and
environmental spills of hazardous substances. The Comprehensive
Environmental Response, Compensation, and Liability Act of 1980
(CERCLA), commonly known as the "Superfund" Act, designated
ATSDR as the lead agency within the Public Health Service to help
prevent or reduce further exposure to hazardous substances and
the adverse health effects that result from such exposures, and
also to expand the knowledge base about such effects.

This publication reports the results and findings of a health
study, registry, or other health-related activity supported by
ATSDR in accordance with its legislative mandate described
above.

Mention of the name of any company or product does
not constitute endorsement by the Agency for Toxic Substances and
Disease Registry, the Public Health Service, or the U.S.
Department of Health and Human Services.

Since 1990, the Agency for Toxic Substances and Disease
Registry (ATSDR) has maintained an active, state-based
Hazardous Substances Emergency Events Surveillance (HSEES)
system to describe the public health consequences associated with
the release of hazardous substances. Five state health departments
participated in the pilot phase of the surveillance system and
began data collection on January 1, 1990. Since 1990, the number
of participating state health departments has increased, with the
largest number of participating states being 14 in 1995 and 1996.
In 1997, the New Hampshire Department of Health and Human
Services voluntarily withdrew from the HSEES system. This
report summarizes the characteristics of events reported to the
surveillance system by 13 state health departments during 1997.

Information on acute hazardous substances emergency events
was collected. The types of data collected included general
information on the event, substance(s) released, victims, injuries,
and evacuations.

Several data sources were used to obtain the maximum
amount of information about each event. These sources included,
but were not limited to, records or oral reports of state
environmental protection agencies, police and fire departments,
and hospitals. The data obtained were computerized using an
ATSDR-provided data entry system and were sent to ATSDR
quarterly.

The 13 states reported a total of 5,531 events for 1997;
approximately 80% of the events occurred at fixed facilities, and
20% were transportation related. In 96% of the events, only a
single substance was released. The most commonly reported
categories of substances were volatile organic compounds; acids;
ammonia; pesticides; other inorganic substances; mixtures
involving more than one category; and the category designated
"other", which included substances that could not be placed in
one of the other 10 categories. During this reporting period, 372
events (approximately 7% of all events) resulted in a total of
1,896 victims. The most frequently reported injuries sustained by
victims were respiratory irritation, headache, eye irritation, and
nausea or vomiting. A total of 28 persons died as a result of all
events, and 514 events required evacuations.

The findings regarding the distribution of the types of
events, the numbers of events with victims and evacuations, and
the injuries reported have, overall, been consistent since HSEES
was begun.

INTRODUCTION

Since 1990, the Agency for Toxic Substances and Disease
Registry (ATSDR) has maintained an active, state-based
Hazardous Substances Emergency Events Surveillance (HSEES)
system to describe the public health consequences associated with
the release of hazardous substances. The decision to initiate a
surveillance system of this type was based on a 1988 study on the
reporting of hazardous substances releases to three national
databases: the National Response Center Database, the Hazardous
Materials Information System (HMIS), and the Acute Hazardous
Events Database (1). A review of these databases indicated that
they were limited because many events were missed through
incomplete reporting (for example, the HMIS does not include
events involving intrastate carriers or fixed-facility events). Other
missing information included the demographic characteristics of
victims, the types of injuries received, and the number of persons
evacuated. As a result of this review, ATSDR implemented the
HSEES system to describe the public health consequences
associated with the release of hazardous substances. The surveillance system has four goals:

To describe the distribution and characteristics of hazardous substances emergencies.

To describe the morbidity and mortality experienced by
employees, responders, and the general public as a result
of hazardous substances releases.

To identify risk factors associated with the morbidity and
mortality.

To identify strategies that might reduce future morbidity
and mortality resulting from the release of hazardous
substances.

This report summarizes the characteristics of hazardous
substances releases and the associated public health consequences
of events reported to the surveillance system during 1997.

Various data sources were used to obtain information about
these events. These sources included, but were not limited to,
records and oral reports of state environmental protection
agencies, police and fire departments, and hospitals. Census data
were used to estimate the number of residents in the vicinity of
the events. All of the data were computerized using an ATSDR-provided
data entry system and were sent to ATSDR quarterly.

Hazardous substances emergency events were defined as
uncontrolled or illegal releases or threatened releases of
hazardous substances or the hazardous by-products of substances.
Not included were events involving petroleum products
exclusively. Events were included if (1) the amount of substance
that was released, or that might have been released, needed (or
would have needed) to be removed, cleaned up, or neutralized
according to federal, state, or local law; or (2) there was only a
threatened release of a substance, but this threat led to an action
(for example, evacuation) that could have affected the health of
employees, responders, or the general public. Victims were
defined as those persons who had at least one injury or died as a
consequence of the event. When counting injuries, victims who
had more than one injury type were counted more than once.
Events were defined as transportation related if they occurred
during surface, air, or water transport of hazardous substances.
Fixed-facility events were defined as events occurring at
industrial sites, schools, farms, or any other type of facility.

For the analyses, the substances released were categorized
into 11 groups. The category "mixtures" consisted of mixtures of
substances from different categories, and the category "other"
consisted of substances that could not be placed in one of the
other 10 substance categories. The category "other inorganic
substances" comprised all inorganic substances except for acids,
bases, ammonia, and chlorine.

RESULTS

A total of 5,531 events were reported in 1997 to the HSEES system by the 13
participating state health departments; of these events, about 1% were only
threatened releases. Eighty percent of the events occurred at fixed facilities,
and 20% were transportation related (Table
1).

Thirty-seven percent of fixed-facility events were reported as involving a
process vessel, which is the reaction chamber where chemicals are processed
(Figure 1). Fifteen percent involved
a type of processing reported as "other", 13% involved storage above ground,
13% involved a combination of types of areas, and 9% involved material handling.
The remaining events involved a variety of areas or the areas were unknown.
In transportation-related events, 81% occurred during ground transport (for
example, truck, van, or tractor), and 14% involved

Factors contributing to fixed-facility events were also reported (Figure
3). In the 4,395 fixed-facility events, 2,597 (59%) involved equipment failure
as a contributing factor to the occurrence of the event. A total of 748 (17%)
fixed-facility events were reported as involving operator error and 114 (3%)
as involving improper filling procedures or overfill.

Ninety-six percent of the events involved the release
of only one substance. Two substances were released in approximately 2% of the
events, and the remainder involved the release of more than two substances (Table
2).

Most releases were either liquid spills (45%) or air emissions
(39%). The remaining releases resulted from fires (4%) or other
types or combinations of types of releases (12%).

Events occurred primarily from 6:00 AM to 12 noon (37%)
and from 12 noon to 6:00 PM (32%). Approximately 19% of
events occurred on a Saturday or Sunday.

Substances

Of the 11 categories into which HSEES substances were
grouped, other inorganic substances (24%), volatile organic compounds (VOCs)
(23%), other substances (16%), mixtures (11%), and acids (7%) were the categories
of substances most commonly released in fixed-facility events (Table
3). In transportation-related events, pesticides (15%), other inorganic
substances (15%), acids (13%), VOCs (11%), and other substances (26%) were most
frequently released. The 100 substances most frequently reported to HSEES for
1997 are listed in Appendix A.

Table 1.--Number of events meeting the surveillance
definition, by state and type of event, Hazardous Substances Emergency Events
Surveillance, 1997.

STATE REPORTING
EVENT

TYPE OF EVENT

TOTAL
NO. OF
EVENTS

FIXED FACILITY

TRANSPORTATION

NO. OF
EVENTS

(%)

NO. OF
EVENTS

(%)

Alabama

122

(81.3)

28

(18.7)

150

Colorado

148

(48.5)

157

(51.5)

305

Iowa

186

(60.6)

121

(39.4)

307

Minnesota

194

(73.2)

71

(26.8)

265

Mississippi

85

(70.8)

35

(29.2)

120

Missouri

113

(61.7)

70

(38.3)

183

New York

366

(89.9)

41

(10.1)

407

North Carolina

117

(73.6)

42

(26.4)

159

Oregon

104

(63.0)

61

(37.0)

165

Rhode Island

27

(73.0)

10

(27.0)

37

Texas

2,457

(90.6)

255

(9.4)

2,712

Washington

260

(70.1)

111

(29.9)

371

Wisconsin

216

(61.7)

134

(38.3)

350

Total

4,395

(79.5)

1,136

(20.5)

5,531

Table 2.--Distribution of the number of substances
released, by type of event, Hazardous Substances Emergency Events Surveillance, 1997.

NO. OF
SUBSTANCES RELEASED

TYPE OF EVENT

ALL EVENTS

FIXED FACILITY

TRANSPORTATION

NO. OF
EVENTS

(%)

NO. OF
SUBSTANCES

NO. OF
EVENTS

(%)

NO. OF
SUBSTANCES

NO. OF
EVENTS

(%)

NO. OF
SUBSTANCES

1

4,260

(96.9)

4,260

1,066

(93.8)

1,066

5,326

(96.3)

5,326

2

82

(1.9)

164

43

(3.8)

86

125

(2.3)

250

3

19

(0.4)

57

13

(1.1)

39

32

(0.6)

96

4

7

(0.2)

28

7

(0.6)

28

14

(0.3)

56

5

9

(0.2)

45

2

(0.2)

10

11

(0.2)

55

6

18

(0.4)

285

5

(0.4)

56

23

(0.4)

341

Total

4,395

(100.0)

4,839

1,136

(100.0)

1,285

5,531

(100.0)

6,124

Table 3.--Distribution of the number of substances
released, by substance category and type of event, Hazardous Substances Emergency
Events Surveillance, 1997.

SUBSTANCE
CATEGORY

TYPE OF EVENT

ALL EVENTS

FIXED FACILITY

TRANSPORTATION

NO. OF
SUBSTANCES

(%)

NO. OF
SUBSTANCES

(%)

NO. OF
SUBSTANCES

(%)

Acids

350

(7.2)

161

(12.5)

511

(8.3)

Ammonia

331

(6.8)

54

(4.2)

385

(6.3)

Bases

135

(2.8)

76

(5.9)

211

(3.4)

Chlorine

110

(2.3)

10

(0.8)

120

(2.0)

Mixtures*

517

(10.7)

56

(4.4)

573

(9.4)

Other inorganic substances

1,155

(23.9)

189

(14.7)

1,344

(21.9)

Other substances

782

(16.2)

335

(26.1)

1,117

(18.2)

Paints and dyes

74

(1.5)

61

(4.7)

135

(2.2)

Pesticides

198

(4.1)

189

(14.7)

387

(6.3)

Polychlorinated biphenyls

81

(1.7)

7

(0.5)

88

(1.4)

Volatile organic compounds

1,106

(22.9)

147

(11.4)

1,253

(20.5)

Total

4,839

(100.0)

1,285

(100.0)

6,124

(100.0)

* Mixtures of substances from different categories.

Victims

A total of 1,896 victims were involved in 372 events
(7% of all events) (Table 4). Of the
events with victims, 51% involved only one victim, and 69% involved either one
or two victims. Most (91%) victims were injured in fixed-facility events.

The substances released most often were not necessarily
the most likely to result in victims (Table
5). For example, VOCs were released during 1,253 events; however, only
46 (4%) of these events resulted in injury. Although chlorine was released in
only 120 events, 34 (28%) of these events resulted in injury, indicating its
greater potential for immediate harm.

The population groups most often injured were employees
(62%) and the general public (31%) (Figure
4). Of the responders who were injured in fixed-facility events, the affiliation
was unknown for 34%; of the remainder, 15% were emergency medical technicians;
15%, firefighters, pay status unknown; 14%, police; and 14%, professional firefighters
(Figure 5). There were 10 responder
victims involved in transportation-related events. Of these victims, 50% were
police officers, and 30% were responders of unknown affiliation.

The types of injuries sustained by victims are shown
in Table 6 and in Figure
6. The victims sustained a total of 3,145 injuries. Some victims had more
than one injury. The most commonly reported injuries in fixed-facility events
were respiratory irritation (39%), headache (13%), nausea or vomiting (12%),
and eye irritation (12%). In transportation-related events, trauma (41%), respiratory
irritation (18%), eye irritation (8%), and headache (7%) were reported most
frequently. Trauma was reported in 41% of transportation-related events and
only 2% of fixed-facility events. The trauma might have been caused by the sequence
of events (for example, a motor vehicle accident) leading to the release of
a hazardous substance and not necessarily by exposure to the hazardous substance
itself.

Table 4.--Distribution of the number of victims by
type of event, Hazardous Substances Emergency Events Surveillance, 1997.

NO. OF
VICTIMS

TYPE OF EVENT

ALL EVENTS

FIXED FACILITY

TRANSPORTATION

NO. OF
EVENTS

(%)

NO. OF
VICTIMS

NO. OF
EVENTS

(%)

NO. OF
VICTIMS

NO. OF
EVENTS

(%)

NO. OF
VICTIMS

1

113

(43.0)

113

76

(69.7)

76

189

(50.8)

189

2

50

(19.0)

100

19

(17.4)

38

69

(18.5)

138

3

26

(9.9)

78

9

(8.3)

27

35

(9.4)

105

4

11

(4.2)

44

1

(0.9)

4

12

(3.2)

48

5

10

(3.8)

50

3

(2.8)

15

13

(3.5)

65

6

53

(20.2)

1,344

1

(0.9)

7

54

(14.5)

1,351

Total

263

(100.0)

1,729

109

(100.0)

167

372

(100.0)

1,896

Table 5.--Number of substances released in all events
and events with victims, by substance category, Hazardous Substances Emergency
Events Surveillance, 1997.

SUBSTANCE
CATEGORY

NO. OF
RELEASES

(%)

NO. OF
RELEASES
WITH VICTIMS

(%)

PERCENTAGE OF
RELEASES WITH
VICTIMS

Acids

511

(8.3)

62

(12.2)

12.1

Ammonia

385

(6.3)

35

(6.9)

9.1

Bases

211

(3.4)

12

(2.4)

5.7

Chlorine

120

(2.0)

34

(6.7)

28.3

Mixtures

573

(9.4)

34

(6.7)

5.9

Other inorganic substances

1,344

(21.9)

103

(20.3)

7.7

Other, not otherwise specified

1,117

(18.2)

131

(25.8)

11.7

Paints and dyes

135

(2.2)

9

(1.8)

6.7

Pesticides

387

(6.3)

41

(8.1)

10.6

Polychlorinated biphenyls

88

(1.4)

1

(0.2)

1.1

Volatile organic compounds

1,253

(20.5)

46

(9.0)

3.7

Total

6,124*

(100.0)

508

(100.0)

8.3

*Total exceeds total number of events (5,531) because events at which more than one substance was released were counted more
than once.

* The number of injuries is greater than the number of victims, because a victim could have had more than one injury.

† Central nervous system.

The sex of 85% of the victims was known; of these victims,
56% were male. Among the population groups, more of the responders (93%) and
employees (61%) were male. The mean age of the victims was 33 years (range:1-89
years). Most (54%) victims were transported to a hospital and treated on an
outpatient basis (Figure 7). Twenty-seven
percent of victims were treated at the scene with first aid; 6% were transported
and admitted to a hospital; 6% were transported to a hospital for observation;
2% had symptoms within 24 hours after the incident that were associated with
the incident and were reported by an official (e.g., personnel with the fire
departments, police, or poison control center); 3% were evaluated by a private
physician within 24 hours after the incident; and less than 2% died.

Among victims, 68% of employees and 26% of responders
had not worn any form of personal protective equipment.
Employees who had worn personal protective equipment most
frequently wore level "D" protection (28%). The personal
protective equipment most frequently worn by first responders
was firefighter turnout gear (27%) and level "B" protection (5%).

A total of 28 persons died as a result of hazardous
substances emergency events. Five persons died in 1 event, 3 in
1 event, 2 in each of 2 events, and 1 in each of 16 separate
events. Unlike previous years of HSEES data collection, the 1997
data involved more deaths resulting from transportation-related
events rather than fixed-facility events. Of the 28 fatalities, 25
resulted from transportation-related events. Of the 28 persons
who died, 24 were male, 19 were employees, and 9 were
members of the general public. There were no deaths among
responders, and there were no members of the general public
killed in fixed-facility events. Twenty-two of the 28 persons who
died had sustained traumatic injuries, 3 had thermal burns, and 3
had both trauma and thermal burns.

Of the 19 employees who died, 13 had not worn personal
protective equipment; 1 had worn level "A" protection; and 1 had
worn level "D" protection. It was unknown whether the
remaining 4 persons had worn personal protective equipment.

Evacuations

Evacuations were ordered in 514 events. Sixty-eight percent
of the evacuations were of a building or the affected part of a
building. Thirteen percent were of a defined circular area around
an event, 11% were based on actual or anticipated downwind
dispersion, 5% were based on a circular and downwind or
downstream area, and 3% were reported as having been ordered
without criteria. The median number of persons evacuated was
20. In 46 events, in-place sheltering was ordered, and instructions
regarding precautions to take during in-place sheltering were
provided in 31 of these events.

Contingency Plans

The types of contingency or preparedness plans used during
an event varied, with 42% involving the use of a company's
operating procedures. Thirty-three percent of events were
reported as involving the use of an incident-specific ad hoc plan,
and 17% involved the use of a hazardous materials (HazMat) or
other response team's standard operating procedures.

SULFURIC ACID

Additional analyses were conducted of events involving
sulfuric acid to determine their association with the adverse public health
consequences of personal injuries and evacuations. Sulfuric acid was the third
most commonly released substance reported to the surveillance system during
1997 (Appendix A). A total of 150 releases
of sulfuric acid were reported to the system. Of these 150 reported releases,
sulfuric acid was the only substance released in 135. Events in which sulfuric
acid was the only substance released were used in the analyses. Seventy-two
percent of sulfuric acid events occurred at fixed facilities, and 28% were transportation
related. For 69% of these releases, there was information on the amount of substance
in gallons. The amounts ranged from 1 to 6,000 gallons, with a median of 30
gallons.

Twelve (9%) of the 135 events that only involved sulfuric
acid resulted in victims. A total of 50 victims resulted from these
12 events. Victims of the sulfuric acid events were primarily
employees (80%) and responders (14%). Six percent of victims
were members of the general public. Injuries resulting from these
events included respiratory irritation (62%), skin irritation (14%),
chemical burns (12%), nausea or vomiting (6%), eye irritation
(3%), trauma (2%), and injuries described as "other" (1%). No
deaths were associated with sulfuric acid releases. Victims were
treated on the scene with first aid (52%), transported and treated
at a hospital but not admitted (40%), or were transported and
admitted to a hospital (8%).

Evacuations were ordered in 12 (9%) of the 135 events
involving only sulfuric acid. Evacuations involved a range of 0 to
200 people. In some events, an evacuation might have been
ordered, but the affected persons did not actually leave their
homes or places of work. The length of evacuation, available for
67% of events, ranged from 1 to 9 hours.

USE OF HSEES DATA

In 1997, ATSDR continued to respond to requests for
HSEES information from local, state, and federal agencies and organizations.
In addition, ATSDR continued to receive requests from researchers from various
countries and territories for the HSEES protocol and data collection form to
help develop similar surveillance systems in their countries. Also, the HSEES
data have been used to produce several publications (Appendix
B).

Future plans for usage of the HSEES system include the
development of an Internet Web site specifically for persons,
organizations, and agencies interested in the activities of the
HSEES program. This Web site will, initially, provide access to
published HSEES annual reports and other information that can
be downloaded to a user's personal computer. Internet linkages
to other relevant Web sites will be available on the HSEES
Web site. Other plans include collaboration with the Federal
Chemical Safety and Hazard Investigation Board and other
agencies and organizations involved with emergency response,
hazardous substances releases, and public health. Additionally, a
project is underway to standardize the names of substances so that
there will be the opportunity to perform substance-specific
analyses in the future.

SUMMARY OF RESULTS, 1990-1997

The number of events, substances released, events with
victims, and deaths for the years 1990 through 1997 are shown in Table
7. In the 8 years of data collection, most events have involved a single
substance and have occurred at fixed facilities. Respiratory irritation has
consistently been reported as the most common injury to victims. In 1997, a
total of 28 fatalities were reported to HSEES. This number was slightly less
than that reported for 1996, even though the reported number of victims in 1997
was greater than in 1996. Most (89%) of the fatalities occurred as a result
of trauma from transportation-related events; however, these deaths were more
likely associated with the occurrence of the event, and not with the substance(s)
involved.

The percentage of events involving victims has remained at
10% or less since 1994. The higher percentage of events with
victims reported in the earlier years, may be due to the under
reporting of events without public health consequences, or due to
the 1993 case definition change. The decrease in the number of
events involving victims could be indicative of increased or
strengthened procedures to protect health and safety. However,
the number of deaths associated with events continues to suggest
the need to evaluate not only the danger posed by exposure to
hazardous substances, but also the circumstances surrounding the
occurrence of events.

Employees continue to be the most commonly reported
victims of emergency events (Figure 8).
Cumulative data on the number of events, substances, victims, and events involving
victims are displayed in Figure 9. Overall,
the results of HSEES data collection have remained fairly consistent throughout
the years.

Findings from HSEES data collection efforts can provide
useful information regarding risk factors related to the occurrence
of emergency events and the associated morbidity and mortality.
This information can be used to develop training and health
education programs for persons involved in hazardous substances
emergency response and planning and for manufacturers and
transporters of hazardous materials.